Abstracts

To investigate the impact of vagus nerve stimulation (VNS) therapy in
institutionalized patients with Lennox-Gastaut Syndrome (LGS) with respect to emergency room (ER) utilization for seizures., We identified patients with LGS from a retrospective chart review of 98 institutionalized patients with epilepsy. LGS was defined when all of the following criteria were met: mental retardation; multiple seizure types; frequent seizures refractory to antiepileptic drugs (AEDs); and prolonged video-EEG monitoring showing 2 of these 5 findings [ndash] slow spike-wave discharges, generalized fast activity, multifocal ([ge]3 sites) epileptiform discharges, tonic seizures and atypical absence seizures. The institution[apos]s protocol specified administration of intrarectal diazepam (Diastat) for seizures or seizure clusters lasting [gt]3 minutes, and transfer to an ER if seizures persisted [gt]10 minutes. Because of frequent seizure clusters in this population, the number of days with documented seizures was counted instead of the actual number of seizures. The comparator group consisted of patients without VNS (non-VNS group) followed over a period of 18 months. The intervention group consisted of those with VNS, and were analyzed in two periods: 6 months before and 6 months after implantation. The primary outcome measure was the number of seizure-related ER visits in the VNS group before and after implantation. Secondary outcome measures were the number of seizure days and the number of Diastat administrations in the VNS group during the same periods. Fixed effects poisson model and poisson regression were used for statistical analysis., There were 9 patients with LGS, and 4 of them had been implanted with VNS. In the non-VNS group, there were 5 patients (3 males), aged 24-53 years. In the VNS group of 4 patients (2 males) aged 25-56 years, the age at implantation was 22-53 years. Compared to non-VNS patients, the VNS patients before implantation had significantly higher Diastat administrations (p[lt]0.0005) and ER visits (p[lt]0.0005) but not seizure days (p=0.06). In the VNS group, during 6 months of follow-up after implantation, the ER visits reduced significantly (10 versus 2, p=0.04), the number of seizure days reduced minimally (107 versus 99, p=0.58) while the number of Diastat administrations increased slightly (36 versus 50, p=0.13)., In a group of institutionalized LGS patients more prone to ER visits, VNS therapy significantly reduced the number of ER visits. The observed trend towards an increase in the administration of Diastat after VNS implantation suggests that the favorable outcome with respect to ER visits may be related to the combined effect of VNS and Diastat in reducing the duration of seizures or seizure clusters. Prospective studies are needed to confirm this and evaluate other potential factors such as VNS parameters and concomitant AEDs influencing this outcome., (Supported by Grant from the state of Kentucky.)